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+ - First Details of Chinese Spacecraft's Asteroid Encounter

Submitted by the_newsbeagle
the_newsbeagle (2532562) writes "Chinese aerospace engineers have revealed, for the first time, details about their Chang’e-2 spacecraft’s encounter with the asteroid Toutatis last month. They have plenty to boast of: The asteroid flyby wasn’t part of the original flight plan, but engineers adapted the mission and navigated the satellite through deep space.

Exactly how close Chang'e-2 came to Toutatis is still unclear. The article states that the first reports “placed the flyby range at 3.2 km, which was astonishingly—even recklessly—tight. Passing within a few kilometers of an asteroid only 2 to 3 km in diameter at a speed of 10 730 meters per second could be described as either superb shooting or a near disaster.” If the Chinese spacecraft did pass that near, it could provide a “scientific bonanza” with data about the asteroid’s mass and composition."

Comment: pulsars are nature's flywheels (Score 1) 325

by Scott Ransom (#36315356) Attached to: Using Flywheels to Meet Peak Power Grid Demands

All of the energy that we see (as well as the energy we don't see, which is the vast majority of it and which comes out in a relativistic particle wind) comes from the rotation of the neutron star. That means that pulsars are flywheels. And amazingly (even to me, and I study them daily), the most energetic pulsars give off tens of thousands of times more power than the total power output of the Sun. And all from rotation. That's crazy.

Damn the Universe is cool.

Comment: Re:Telescope in West Virginia (Score 4, Informative) 248

by Scott Ransom (#36136406) Attached to: Search For Alien Life On 86 Planets Begins

Actually, they aren't using the GBT's spectrometer. They are using an instrument that I helped to develop for pulsar research called GUPPI, which uses FPGAs and GPUs to real-time process 800MHz of radio bandwidth.

However, in this case they are using GUPPI's GPU nodes to record 800MHz of Nyquist-sampled band centered at 1.5GHz. Each sample is 2-bits, and with 2 polarizations, that is how they get 800MB/s (or almost a GB/s as it says in the article).

If you want some basic info about GUPPI, you can find it here:

https://safe.nrao.edu/wiki/bin/view/CICADA/NGNPP

Comment: more detail needed (Score 1) 85

by p_trekkie (#33109010) Attached to: Equatorial Mounts For Budget Astrophotography?
I think you may be asking for the impossible. Well maybe not. I think that your question needs more details. The following information would be useful:
  • What you are mounting on the equatorial mount? Is it a telescope or a camera? How big of a telescope?
  • What are you trying to photograph

If you are trying to photograph deep sky objects through a mid sized telescope, I don't think you will find a mount in your budget range, unless you can get one used off of ebay or some such. The tabletop equatorial mount might be appropriate if you're just doing the sky. However, for a telescope, just the motors for a good equatorial drive will set you back $100 or more....

If you are only trying to photograph planets or the moon, you won't need any tracking ability to get spectacular photographs.

Comment: Re:But what about the massive environmental damage (Score 1) 325

by p_trekkie (#30544798) Attached to: "Home Batteries" Power Houses For a Week
Actually, Lithium is one of the least abundant elements in the universe, at least in terms of elements that don't decay radioactively. Quoth wikipedia:

Though very light in atomic weight, lithium is less common in the solar system than 25 of the first 32 chemical elements.

The lack of lithium in the universe is one of the great unsolved mysteries in astronomy.

Comment: Re:A complementary approach (Score 5, Informative) 190

by Scott Ransom (#29434879) Attached to: A Galaxy-Sized Observatory For Gravitational Waves

The good thing is that the pulsars which glitch are the young ones (hundreds to millions of years old). The pulsars that we are using for NANOGrav are millisecond pulsars which are hundreds of millions or billions of years old, have much smaller magnetic fields than young pulsars, and basically never glitch. They are extremely stable rotators -- much better than normal pulsars.

Science

Darwin's Voyage Done Over, Live 147

Posted by timothy
from the it-was-live-the-first-time-too dept.
thrill12 writes "Almost 178 years ago, Charles Darwin set sail in the HMS Beagle, to do the now famous explorations that formed the basis for Darwin's On The Origin Of Species. Now, a group of British and Dutch scientists, journalists and artists set sail again to redo the voyage of the Beagle. This time, they are taking modern equipment with them and they have live connections through Twitter, Youtube, Facebook and Flickr. As they re-explore, and (re)discover, we can join that 8-month-long trip, live over the internet."

Comment: Re:Back in the day... (Score 3, Interesting) 629

by p_trekkie (#28927841) Attached to: RadioShack To Rebrand As "The Shack"?
Actually, they still sell logic chips and miscellaneous electronic components, albeit fairly well-hidden in the back of the store. I had a last minute idea for a project for a summer camp group I was leading last week and was able to pick up all the components I needed from RadioShack. Admittedly, the selection isn't what it used to be, but it's still there when you have a sudden pressing need for resistors, LEDs, transistors and capacitors....

Who knows what this "rebranding" will do for that section of the store....

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